The (Dysfunctional) Crystal Radio

With a couple of household items and a crystal earplug an AM radio can be built (maybe)!

This is a great project for the Jr. scientist/physicist in your heart!

First acquire:

Lots of wire (enamel coated)

One 47,000 ohm resistor

Crystal earplugs (good luck finding them)

A cylindrical tube (like the kind found inside a roll of paper towels)

Alligator clips

Germanium or silicon diode

These are the schematics for the AM radio:

Now using the towel paper tube wrap many turns of wire
making sure they do not cross. Next, scratch off a thin line of the enamel
coating off of the coil. Now create the circuit part of the radio and connect the
diode the earplug and the resistor in the fashion shown below. Make sure the
circuit is grounded (the alligator clips may be used for this) and also the
wire on the towel paper tube. Lastly the antenna is just wire that is connected
to the top of the cylindrical tubes wire and extends in on direction above
ground. Do not let the antenna touch anything metal.

The wire before the diode is placed against different points
along the exposed wire on the tube. This will tune your radio. You should be
able to hear something.

Unfortunately our group was unable to obtain the most
crucial component of this experiment, the crystal earplug. So we used an
amplifier and a speaker to attempt to hear our radio. We took apart some audio
cables and we attached one where the earpiece used to be as shown below.

Next we plugged the plug into the aux input on a mini stereo
system. The speaker was plugged into the right output. Now we checked to see if
everything was properly grounded before plugging in the amplifier. We turned on
the equipment and all we heard was static. Then we attempted to tune it by
rubbing the wire before the diode against the exposed wire on the cylindrical
tube. Upon contacting the wire with the cylindrical tube's wire we heard a
staticky hum. We asked Mr. Elert whether the radio was working. He said it was but
it was picking up interference from the laptops. We also learned that radio
signals don't travel well or at all through reinforced concrete buildings like our
beloved Midwood High School.